High-DNA integrity sperm selection using rheotaxis and boundary following behavior in a microfluidic chip

Area of Science:

• Biomedical Engineering
• Reproductive Biology
• Microfluidics

Background:

• Rheotaxis is a natural sperm guidance mechanism used in microfluidics for sperm separation.
• Existing rheotaxis devices lack DNA integrity assessment and specific cell separation capabilities.
• These limitations hinder practical applications in assisted reproduction.

Purpose of the Study:

• To develop a microfluidic chip for efficient separation of highly motile sperm.
• To address limitations of previous rheotaxis-based sperm separation methods.
• To improve sperm quality for assisted reproductive technologies.

Main Methods:

• Designed a microfluidic chip with boomerang-shaped channels utilizing sperm rheotaxis and boundary-following behavior.
• Employed Finite Element Method (FEM) simulations to predict sperm trajectories.
• Experimentally validated device performance for sperm separation and classification.

Main Results:

• Separated over 16,000 motile sperm in under 20 minutes, suitable for droplet-based IVF.
• Classified sperm into highly motile (>120 μm s⁻¹) and motile (<120 μm s⁻¹) groups.
• Achieved significant improvements: 45% in motility, 20% in highly motile sperm count, and 80% in DNA integrity.

Conclusions:

• The developed microfluidic chip effectively separates highly motile sperm using rheotaxis.
• The device enhances sperm quality, showing significant improvements in motility and DNA integrity.
• This technology holds promising potential for improving assisted reproduction outcomes.